The present disclosure relates to a wind farm, a control method thereof and a wind power generation unit, and more particularly, to a wind farm which protects a wind power generation unit by sensing risk factors of the external environment which is suddenly changed, a control method of the wind farm, and a wind power generation unit.
Wind power generation relates to the conversion of a rotational energy of blades rotating using kinetic energy of wind into electric energy. Recently, wind power generation is in the limelight as eco-friendly energy which does not generate green-house gases.
FIG. 1 illustrates components of a conventional wind power generation unit, and FIG. 2 illustrates a general wind farm and risk factors of the external environment.
For wind power generation, a single wind power generation unit may be installed locally, but in the majority of cases, dozens or hundreds of wind power generation units 20 form a wind farm 10.
The wind power generation units 20 may use kinetic energy of wind, and sensitively react according to changes in external weather environment.
The wind power generation units 20 generally carry out a yawing control to horizontally rotate a nacelle 8 according to a change of wind direction. Moreover, the wind power generation units carry out a pitch control to adjust a pitch angle of blades 2 according to a change of wind speed, so as to prevent a damage of the individual wind power generation unit by inducing the optimum aerodynamic performance and by adjusting a rotational speed when excessively strong wind blows.
In the meantime, through such pitch control and yawing control, the individual wind power generation unit is controlled on the basis of weather observation and information measured by a weathercock 7 and a wind gauge 6 mounted on the wind power generation unit. However, when there is a sudden weather variable which is not forecasted by the weather observation, a predictive control may not be possible, and the individual wind power generation unit may be damaged while the weathercock 7 and the wind gauge 6 are detecting the weather variable.
When a severe local weather change, such as windstorm, tornado, or a local gust of wind, occurs, the wind power generation unit 20 which works normally may be fatally damaged before a control is carried out even though it sensed a risk element.
Particularly, in case of a sudden change in wind direction and wind speed, the unit 20 is damaged due to an excessive increase of rotational speed and vibration of the blades 2.
Moreover, in case of windstorm, sand particles collide against the rotating blades 2, so that the surface coating and the appearance of the blades are damaged and the aerodynamic performance of the surfaces of the blades 2 is deteriorated.
That is, when there is an unexpected change in weather, all of the wind power generation units 20 arranged in the conventional wind farm 10 may be damaged.